Cable based lift systems are used in conjunction with track rail or bridge and trolley systems, to move cable suspended payloads. Movement along two horizontal axes can be obtained by moving a bridge on fixed rails along a first axis, then moving a trolley along the bridge along a second horizontal axis, in a direction perpendicular to the direction of the fixed rails. The cable system provides vertical lift assistance, typically through a hoist which may be motorized. The operator physically pushes and pulls the cable suspended payload to start, continue, slow or stop the horizontal movement of the payload. The starting-and-stopping strain on the operator, when the operator must overcome maximum inertia of the payload, is a known ergonomic problem with these types of systems.
A cable lift system with horizontal movement assistance exists which is actuated by an angular deviation of the payload suspending cable from a vertical position. However, horizontal assistance is only actuated after the angle of the cable is deviated from a vertical position, e.g., after the operator has become strained by inputting a manual starting or stopping force against the payload. Because horizontal assistance is not actuated until after the operator has exerted force against the payload to cause the cable to deviate from vertical, this type of device does not address the known ergonomic problem. Another device to provide horizontal assistance includes a vertical column and handle bar arrangement which is disadvantaged by high cost, limited flexibility, increased weight and non-intuitive operator controls.